diff --git a/lms/static/js/ie11_find_array.js b/lms/static/js/ie11_find_array.js
index 4d3c36fd42..57bccb57f8 100644
--- a/lms/static/js/ie11_find_array.js
+++ b/lms/static/js/ie11_find_array.js
@@ -1,28 +1,32 @@
 // Polyfill for patching IE11 Browsers
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find#Polyfill
+"use strict";
+
 if (!Array.prototype.find) {
-  Object.defineProperty(Array.prototype, 'find', {
-    value: function(predicate) {
-     // 1. Let O be ? ToObject(this value).
-      if (this == null) {
-        throw new TypeError('"this" is null or not defined');
-      }
+    Object.defineProperty(Array.prototype, 'find', { // eslint-disable-line no-extend-native
+      value: function(predicate) {
+        var o, len, thisArg, k, kValue;
 
-      var o = Object(this);
+        // 1. Let O be ? ToObject(this value).
+        if (this == null) {
+          throw new TypeError('"this" is null or not defined');
+        }
 
-      // 2. Let len be ? ToLength(? Get(O, "length")).
-      var len = o.length >>> 0;
+        o = Object(this);
 
-      // 3. If IsCallable(predicate) is false, throw a TypeError exception.
-      if (typeof predicate !== 'function') {
-        throw new TypeError('predicate must be a function');
+        // 2. Let len be ? ToLength(? Get(O, "length")).
+        len = o.length >>> 0;
+
+        // 3. If IsCallable(predicate) is false, throw a TypeError exception.
+        if (typeof predicate !== 'function') {
+          throw new TypeError('predicate must be a function');
       }
 
       // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
-      var thisArg = arguments[1];
+      thisArg = arguments[1];
 
       // 5. Let k be 0.
-      var k = 0;
+      k = 0;
 
       // 6. Repeat, while k < len
       while (k < len) {
@@ -30,7 +34,7 @@ if (!Array.prototype.find) {
         // b. Let kValue be ? Get(O, Pk).
         // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
         // d. If testResult is true, return kValue.
-        var kValue = o[k];
+        kValue = o[k];
         if (predicate.call(thisArg, kValue, k, o)) {
           return kValue;
         }